Username = "admin"
Password = "123"
for i in [1,2,3]:
    username=input("请输入用户名：")
    password=input("请输入密码：")
    if Username==username and Password==password:
        print(f"欢迎{Username}。")
        break
    else:
        if i<3:
            print(f"录入错误，你还有{3-i}次机会。")
        else:
            print("登录超时，请明天再登录。")